Vibration isolation fastener insert

ABSTRACT

A vibration isolation fastener insert structure adapted to be partially or wholly snugly received in a hole in a panel comprising: 
     a rigid cylindrical hub having an externally extending flange and a through longitudinal opening adapted to receive a fastener element; 
     an elastomeric bushing snugly carried or formed around said hub and having a slot therein receiving said external flange; 
     an upper housing; 
     a lower housing; 
     the upper housing being disposed around the side of said bushing and having a flange over the top of said bushing and the lower housing disposed around the external side of said upper housing and having a flange extending below a lower surface of said bushing.

BACKGROUND OF THE INVENTION

This invention relates to a vibration isolation insert device thatserves the purpose of dampening vibrations while fasteningstructures/assemblies together or installing assemblies to a vibratingstructure. This insert device can be installed on a monument, assembly,panel, plate or in a composite panel to assemble or install a componentpart on an aircraft, moving vehicle, or vibrating structure.

The effects of vibrations are a problem in commercial aircraft. Forexample, vibration is transmitted by the structural beams which supportthe floor panels. These floor panels are typically made of an aluminumhoneycomb, or other rigid, lightweight material and vibration causes thepanels to vibrate which creates sound. This background sound can beunpleasant and interfere with ordinary conversation, disturb sleep andthe like. Other structures or monuments normally found in aircraftinteriors such as seats, galleys, bulkheads, etc. supported by the baseairframe structure are also subject to vibration and the creation ofunwanted sound and noise.

All of the effects are undesirable and reduce the flying customer'scomfort and satisfaction.

The practice of using isolators on vehicles is longstanding. They areused to reduce noise and eliminate the transfer of isolating frequenciesto the passenger cabin, thereby reducing perceived noise and reducingpassenger fatigue. It has been common practice to isolate monuments(e.g., furnishings) and/or added components on an aircraft or vehicleswith the use of external isolator mounts (i.e., isolating devicesmounted to the aircraft or vehicle structure). These isolator mountsgenerally require additional brackets, fasteners and other adapters inorder to make isolation functional in a vibrating environment.

U.S. Pat. No. 6,443,679 issued to Schwarz on Sep. 3, 2002 shows avibration-dampening connecting arrangement for the detachable connectionof two components with a releasing part, which can be moved on a boltguided by a bush. U.S. Pat. No. 7,179,039 issued to Schwartz et al. onFeb. 20, 2007 shows a vibration-damping ring insert arrangement andcomponent connection arrangement incorporating the same. U.S. Pat. No.5,876,023 issued to Hain et al. on Mar. 2, 1999 and companion U.S. Pat.No. 5,876,024 shows a vibration isolation insert for aircraft floorpanels and the like. U.S. Pat. Nos. 6,065,742, 6,138,980, 6,216,833 B1,6,394,432 B1, 6,715,746 and Enidine GmbH U.S. Pat. No. 7,131,786 B2 arealso patents in this field.

SUMMARY OF THE INVENTION

A vibration isolation fastener insert structure adapted to be partiallyor wholly snugly received in a hole in a panel comprising:

a rigid cylindrical hub having an externally extending flange and acentral through longitudinal opening adapted to receive a fastenerelement;

an elastomeric bushing snugly carried or formed around said hub andhaving a slot therein receiving said externally projecting flange;

an upper housing;

a lower housing;

the upper housing being disposed around the side of said bushing andhaving a flange over the top of said bushing and the lower housingdisposed around the external side of said upper housing and having aflange extending below a lower surface of said bushing.

A vibration isolation fastener insert structure adapted to be partiallyor wholly snugly received in a hole in a panel comprising:

a rigid cylindrical hub having an externally extending flange and acentral through longitudinal opening adapted to receive a fastenerelement;

an elastomeric bushing snugly carried or formed around said hub andhaving a slot therein receiving said externally projecting flange;

an upper housing;

a lower housing;

the upper housing being disposed around the side of said bushing andhaving a flange over the top of said bushing and the lower housingdisposed around the external side of said upper housing and having aflange extending below a lower surface of said bushing, said lowerhousing being externally threaded.

A panel assembly having a through hole, at least partially snuglyreceived in said hole a vibration isolation fastener insert comprising:

a rigid cylindrical hub having an externally extending flange and acentral through longitudinal opening adapted to receive a fastenerelement;

an elastomeric bushing snugly carried or formed around said hub andhaving a slot therein receiving said externally projecting flange;

an upper housing;

a lower housing;

the upper housing being disposed around the side of said bushing andhaving a flange over the top of said bushing and the lower housingdisposed around the external side of said upper housing and having aflange extending below a lower surface of said bushing,

the upper housing being disposed around the side of said bushing andhaving a flange over the top of said bushing and the lower housingdisposed around the external side of said upper housing and having aflange extending below a lower surface of said bushing, said lowerhousing being externally threaded.

A panel assembly, said panel having a through hole, and upper and lowerflanges, the upper flange having a cylindrical element being snuglyreceived in said through hole and the lower flange having a cylindricalelement being threadably received in said upper flange and carryinginwardly projecting threads,

a vibration isolation fastener insert structure partially or whollyinserted in said hole in said panel and comprising:

-   -   a rigid cylindrical hub having an externally extending flange        and a central through longitudinal opening adapted to receive a        fastener element;    -   an elastomeric bushing snugly carried or formed around said hub        and having a slot therein receiving said externally projecting        flange;    -   an upper housing;    -   a lower housing;    -   the upper housing being disposed around the side of said bushing        and having a flange extending over the top of said bushing and        the lower housing disposed around the external side of said        upper housing and having a flange extending below a lower        surface of said bushing, said lower housing being externally        threaded,        said external threads on said lower housing being made up with        the inwardly projecting threads on said lower flange.

The invention is directed to aircraft having fastener insertsincorporated in a member which can be a honeycomb or composite or metalpanel forming composite part of the floor, seat, overhead locker, etc.or sheet metal or plate component to support avionic equipment or thelike. This invention can also be applied directly to the airframe metalstructure as a swaged insert on to the metal structure in similar manneras to plate or sheet metal.

In one preferred embodiment, a thru hole is cut in the panel, the upperand lower flanges are pressed in and the flanges are also bonded on theskins of the panel with adhesive then potting material is injected toform the “desification”.

Separately, the upper and lower housing with the “C” cross-sectionshaped elastomeric bushing and hub are assembled. An elastomeric spacerring can be dropped into place if spacing is desired. Then the abovedescribed assembly is threaded into place, female threads on the lowerhousing engaging the inwardly projecting male threads on the lowerflange. The assembly can be advanced as desired.

The purpose of the elastomeric bushing is to provide a vibrationdampener between the two structural parts. The nut, bolt and seat trackdo not form part of the invention but do show how the insert is used.

The “potted-in” embodiment is preferred but not a limitation since thefastener inserts can be held in, for example, a metal sheet or directlyto the airframe panel by force or interference fit, viz., swaging orbonded-on.

In case of application directly to sheet metal, plate or airframe metalstructure, isolator insert will be swaged to metal in similar manner asa rivet or clinch nut.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention incorporates a vibration isolation insert as a permanentcomponent of the monument, panel, assembly, plate and/or composite panel(hereafter collectively called monument). This insert device isassembled with an internal elastomer with dampening characteristics thatcan be modulated to accommodate different frequencies. Its variousembodiments allow for an infinite number of permutations.

For example, the fastener inserts are used in floor panels to fasten thefloor panel to a structural floor track or beam. Other uses are tofasten seats, galleys, overhead lockers, bulkheads, lavatories and thelike.

The invention includes an elastomeric part within the fastener insert,to isolate, for example, the floor from structural vibration within themain structural framework of the aircraft and thereby make the passengercompartment more comfortable and pleasing to the passenger.

THE DRAWINGS

The basic design of one embodiment of a panel assembly with thevibration isolation insert in place is as shown in cross-section in FIG.1.

FIG. 2 shows another embodiment of the invention in cross-section.

FIG. 3 shows one application of the vibration isolation insert of FIG.2.

FIG. 4 shows another application of the vibration isolation insert ofFIG. 3.

Turning to FIG. 1 in more detail, the insert 10 is adapted to bereceived in a hole 12 drilled in panel 14, typically a honeycomb panel.In use, the upper and lower flanges 16 and 18 are inserted into hole 12and held by an interference or press fit, i.e., swaged. Alternatively,the flanges 16 and 18 can be potted in by a liquid potting compound orglue, injected via potting holes 17, which, after injection, hardens andadheres to surfaces of upper flange 16 and lower flange 18 and toexposed cells within the honeycomb panel 14, holding the flanges inplace. The flanges are usually bonded on first with an adhesive and thenpotted-in with a potting compound.

Next, the upper housing 20, lower housing 22 having external malethreads, elastomeric bushing 24, hub 26 are pre-assembled with theexternal flange 27 on hub 26 being received in slot 25 in elastomerbushing 24 and the so sub-assembly threaded into the female threads onupper flange 16. The elastomer can be over-molded onto hub 26 wherebythe holes on hub are used for anti-rotation and increased bondingsurface for the elastomer. Finally, a nut 28 and bolt 30 are insertedand made up to join the panel 14 to the structural track 32.

Turning to FIGS. 2 a, 2 b and 2 c of 2, the drawings, in this embodimentthe upper flange 116 and the lower flange 118 are press fit, screwed orswaged to each other and capture components. The elastomeric bushing 124and hub 126 (elastomer/metal hub assembly) are positioned as shown. Thedimensions and materials for flange 116 and flange 118 will depend onthe type and size of fasteners (e.g., screw, anchor, etc.) used tosecure the monument to the vehicle structure and the material into whichit will be installed. Flange 116 and flange 118 will accommodatedifferent applications whereby the overlying elements 119 on flanges 116and 118 may be omitted and the balance of the flanges 116 and 118 areflush with the surface of the panel 110 or may overlap the surface(s) ofthe panel 110 to increase the strength of the insert under varioustensile, shear or torsion loading conditions. The holes 117 are for theinjection of potting material and venting of air as potting is carriedout.

Hub 126 is to be cylindrical in shape with a circular “T” flange 127intersecting the cylinder. The flange 127 component on hub 126 arelarger than the clearance hole openings on flanges 116 and 118 such thatit is retained if pulled axially, even if elastomeric bushing 124 wouldfail. Hub 126 may be threaded internally to accept any size screw or itcan remain unthreaded or through-drilled to act as a bushing, eitherwith/without a countersink on either end to accommodate a flat-headscrew. Hub 126 may also be threaded externally at its exposed end toaccept adapters of different sizes. The diameter dimensions and finishesof hub 126 may vary to accommodate various size screws, and toaccommodate strength requirements.

Elastomeric bushing 124 may have ribs or projections 130 to provideanti-rotation elements which can engage slots 128.

Flange 118 may have a snap ring 131 to facilitate engagement with snapgroove 129 on flange 116.

Elastomeric bushing 124 may or may not be bonded to hub 126 such as bymolding and will have the required characteristics to provide theoptimum dampening under the loads for each condition. Various dampeningeffects can be achieved by modifying the material characteristics anddimensions of elastomeric bushing 124.

Optionally, flange 116 may have an anti-rotation knurled ring or area133.

Hub 126 may have holes 132 in flange 127 to allow for over-molding ofelastomer and thereby prevent relative rotation. Hub 126 as shown, forexample, in FIG. 2 c may have self-locking internal threads. Theexternal threads may also be self-locking. Hub 126 may also be doubleended, that is, have a flange at both of its ends.

As shown in FIG. 3, two honeycomb panels can also be joined and held inspaced apart relationship using a stand off 134.

FIG. 4 shows the vibration isolation fastener in a panel used to join toanother panel with separation provided by standoff 134.

As shown in FIGS. 3 and 4, the assembly can be secured by anti-rotationhex nut 135.

This invention lends itself to include the development of a family ofinsert types that will address many applications and uses. This familyof inserts may be viewed in two general categories: Potted IsolatorInserts and swaged Isolator Inserts. The Potted Isolator Insert categorywould typically be installed through a honeycomb panel attached to (orpart of) the monument, and would be secured via the application of apotting compound in the panel cavity surrounding the installed insertand possibly via bonding to flanges of components 116 and 118. Theswaged Isolator Insert embodiment would typically be installed in apanel attached to (or part of) the monument by crimping its outerflange(s) after the Insert is installed in a receiving hole on thepanel. A panel could be a plate, a group of stacked plates or the web ofan extrusion of any type of material depending on the application.Honeycomb panels are panels manufactured with two rigid skins and alightweight core. Generally, honeycomb panels come in many thicknessesand vary in core material, core density, skin materials, skin thickness,and adhesive type.

The installation and application of these inserts include many fasteningmethods for us with the various fastener types and sizes commonly usedin aircraft and other vehicles. The family of Isolator Inserts of thisinvention will accommodate typical metric and Imperial fastener sizes,and will address derivatives that include studs, through fasteners,threaded fasteners, and additional attachments.

The Potted Isolator Insert category will include, among otherembodiments:

1. Adjustable threaded hub w/an assembled outer ring assembly.

2. Adjustable threaded hub w/an un-assembled 2-piece plug/sleeveassembly for adjustability.

3. When addressing bulkhead or vertical panel applications the hub willhave bi-directional extensions, extending on opposite directions. Thesemay also be threaded or not internally and externally.

4. Inserts as noted: fully assembled and ready for installation; or anun-assembled insert in three or five parts (i.e., flanges andelastomeric bushing/hub assembly) to be assembled and installed bycustomer.

The swaged Isolator Insert category will include, among otherembodiments:

1. Adjustable threaded hub w/an assembled outer ring assembly to bepress fit into a panel hole.

2. Adjustable threaded hub w/an un-assembled 2-piece flanges assembly tobe press fit or threaded upon installation.

3. Inserts as noted: fully assembled and ready for installation; or anun-assembled insert in three or five parts (i.e., flanges and elastomerbushing/hub assembly) to be assembled and installed by customer.

1. A vibration isolation fastener insert structure adapted to bepartially or wholly snugly received in a hole in a panel comprising: arigid cylindrical hub having an externally extending flange and acentral through longitudinal opening adapted to receive a fastenerelement; an elastomeric bushing snugly carried or formed around said huband having a slot therein receiving said externally projecting flange;an upper housing; a lower housing; the upper housing being disposedaround the side of said bushing and having a flange over the top of saidbushing and the lower housing disposed around the external side of saidupper housing and having a flange extending below a lower surface ofsaid bushing.
 2. A vibration isolation fastener insert structure adaptedto be partially or wholly snugly received in a hole in a panelcomprising: a rigid cylindrical hub having an externally extendingflange and a central through longitudinal opening adapted to receive afastener element; an elastomeric bushing snugly carried or formed aroundsaid hub and having a slot therein receiving said externally projectingflange; an upper housing; a lower housing; the upper housing beingdisposed around the side of said bushing and having a flange over thetop of said bushing and the lower housing disposed around the externalside of said upper housing and having a flange extending below a lowersurface of said bushing, said lower housing being externally threaded.3. A panel assembly having a through hole, at least partially snuglyreceived in said hole a vibration isolation fastener insert comprising:a rigid cylindrical hub having an externally extending flange and acentral through longitudinal opening adapted to receive a fastenerelement; an elastomeric bushing snugly carried or formed around said huband having a slot therein receiving said externally projecting flange;an upper housing; a lower housing; the upper housing being disposedaround the side of said bushing and having a flange over the top of saidbushing and the lower housing disposed around the external side of saidupper housing and having a flange extending below a lower surface ofsaid bushing, the upper housing being disposed around the side of saidbushing and having a flange over the top of said bushing and the lowerhousing disposed around the external side of said upper housing andhaving a flange extending below a lower surface of said bushing, saidlower housing being externally threaded.
 4. The panel assembly of claim3 wherein the panel is honeycomb.
 5. The panel assembly of claim 3wherein said vibration isolation fastener insert is swaged into saidpanel.
 6. The panel assembly of claim 3 wherein said vibration isolationfastener insert is potted into said panel.
 7. A panel assembly, saidpanel having a through hole, and upper and lower flanges, the upperflange having a cylindrical element being snugly received in saidthrough hole and the lower flange having a cylindrical element beingthreadably received in said upper flange and carrying inwardlyprojecting threads, a vibration isolation fastener insert structurepartially or wholly inserted in said hole in said panel and comprising:a rigid cylindrical hub having an externally extending flange and acentral through longitudinal opening adapted to receive a fastenerelement; an elastomeric bushing snugly carried or formed around said huband having a slot therein receiving said externally projecting flange;an upper housing; a lower housing; the upper housing being disposedaround the side of said bushing and having a flange extending over thetop of said bushing and the lower housing disposed around the externalside of said upper housing and having a flange extending below a lowersurface of said bushing, said lower housing being externally threaded,said external threads on said lower housing being made up with theinwardly projecting threads on said lower flange.
 8. The panel assemblyof claim 7 wherein the panel is honeycomb.
 9. The panel assembly ofclaim 7 wherein said vibration isolation fastener insert is swaged intosaid panel.
 10. The panel assembly of claim 7 wherein said vibrationisolation fastener insert is potted into said panel.